Question?
Are these Rabbits all in onePen? If they are They need to beseperated , especially IF you have no clue which isMale and which is Female .Generally the Male wont kill thebabies, The FemaleWILL. Especially ifshe precieves the Male as a threat , which shewill.
Rabbits shouldnt be allowed to breedbefore 6 months old Irrigardless of the Breed .They are not experienced enoughMothers at this age and suchincidence as thiscan and willhappen.
There are many things that can go wrong , Fetaldeath being one of them . TheDoe could have also Died.
Best Advice I can give you right now isto Seperate them . If You cantput them in seperate cages finda way to block off the one they are, split it in half so they haveno direct contact with eachother , but can smell and interact witheach other thru the wire.